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Home >> Lexus >> 2021 >> RX 350L AWD >> Repair and Diagnosis >> Transmission >> Transfer Case >> Dynamic Torque Control AWD System - Diagnostic Codes & Circuit Tests >> Dynamic Torque Control AWD System >> DTC U0100/85: Lost Communication with ECM / PCM "A"; DTC U0126/84: Lost Communication with Steering Angle Sensor Module; DTC U0129/83: Lost Communication with Brake System Control Module [09/2015 - 08/2019] >> Description
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DTC U0100/85: Lost Communication with ECM / PCM "A"; DTC U0126/84: Lost Communication with Steering Angle Sensor Module; DTC U0129/83: Lost Communication with Brake System Control Module [09/2015 - 08/2019]: Description

The 4WD ECU assembly receives signals from the ECM, skid control ECU (brake actuator assembly) and steering sensor via CAN communication.

When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before repairing each corresponding sensor.

DTC No. Detection Item DTC Detection Condition Trouble Area
U0100/85 Lost Communication with ECM / PCM "A"
  1. When both of the following continue for 2 seconds or more:
    • The IG 1 terminal voltage is 10 V or more.
    • At a vehicle speed of 60 km/h (38 mph) or more, communication with the ECM cannot be performed.
  • CAN communication system
  • 4WD ECU assembly
  • ECM
U0126/84 Lost Communication with Steering Angle Sensor Module
  1. When both of the following continue for 1 second or more:
    • The IG 1 terminal voltage is 10 V or more.
    • Communication with the steering sensor cannot be performed.
  2. When all of the following occur 10 times consecutively:
    • The IG 1 terminal voltage is 10 V or more.
    • A communication malfunction with the steering sensor occurs once within 5 seconds, 10 times or more within 60 seconds.
  • CAN communication system
  • 4WD ECU assembly
  • Steering sensor
U0129/83 Lost Communication with Brake System Control Module
  1. When the following continues for 3 seconds or more:
    • The IG 1 terminal voltage is 10 V or more.
    • Communication with the skid control ECU (brake actuator assembly) cannot be performed.
  • CAN communication system
  • 4WD ECU assembly
  • Skid control ECU (Brake actuator assembly)